Irrigation systems are commonly used to compensate for inadequate rainfall by artificially watering turf or other landscape. In their most basic form, irrigation systems comprise water supply lines that direct water to a group of sprinklers. Each sprinkler is placed at varying positions around the landscape, preferably maximizing the area on which water is disbursed.
Control of each sprinkler is typically left to valves coupled to the water supply lines, preventing or allowing water to flow to each of the sprinkler heads. In some residential and commercial irrigation systems, electrically controlled solenoid valves are operatively connected to a central irrigation controller. These irrigation controllers include a microprocessor with an input interface (such as a dial and buttons) where a user can program a desired watering schedule. When the watering schedule calls for irrigation of at least a portion of the landscape, the irrigation controller causes one or more solenoid valves to open so that water flows to their respective sprinklers. When the schedule calls for an end to the irrigation, the irrigation controller causes the solenoid valves to close, stopping the water flow to the sprinklers.
Large commercial irrigation systems, such as those used for golf courses, generally operate in a similar manner to the previous description. However, the complexity of managing larger irrigation systems increases as the number of sprinklers and the area they irrigate increases. For example, different locations may require dramatically different amounts of water, due to installation of new grass, valleys that collect water, variation in soil composition, or even different grass types. Consequently, additional hardware and software are used for more precise control over the system, increased system reliability, irrigation performance, ease of maintenance, and many other benefits.
In one popular irrigation system arrangement, a central controller is provided which communicates with multiple satellite controllers. Each satellite controller then communicates with solenoid valves either upstream of a group of sprinklers or built into each sprinkler's body for individual sprinkler control. In some systems, users connect the power wires of multiple solenoid valves to one irrigation station terminal on the satellite controller to save wire and conserve irrigation stations. In any of these arrangement, the satellite controller dictates which solenoid valves should be activated for distributing water. Examples of such a prior art irrigation system are disclosed in U.S. Pat. Nos. 4,101,786 and 4,244,022, each of which are incorporated herein by reference in its entirety.
The user operates the irrigation system by programming an irrigation schedule into the central controller which provides a timetable and possibly a set of sensor conditions that must be met for irrigation to occur. This schedule is then communicated to each satellite controller which implements the program for the groups of solenoid valves ultimately connected to it.
Preferably, satellite controllers have a wide range of functionality to allow the user flexibility in how the satellite controller is implemented in the irrigation system. Specifically, the satellite controllers typically have a user interface which allows the user to modify the irrigation schedule for the sprinklers connected to that specific satellite controller and possibly the schedules of other controllers as well. Thus, if the user observes a problem, such as a dry area that requires more water, the irrigation schedule for the problem area can be conveniently modified at the nearby satellite controller, instead of the distant central controller. However, modifying programs for many irrigation stations (i.e. solenoid valves) can be time consuming with the limited user input controls of the satellite controller and the many schedule-programming options available for each station.
Another functionality typically included in satellite controllers is multiple expansion slots for inserting additional station cards. As their name suggests, the station cards provide additional terminals to connect additional solenoid valves, thus expanding the number of sprinklers controlled by the satellite controller. While allowing for convenient station upgrades, prior art satellite controllers require that additional station cards be inserted in ascending slot order (e.g., if slot 1 is filled, an expansion card must be inserted into slot 2). Further, these slots lack the flexibility to alternately accept sensor cards (e.g., a card that connects to a soil moisture sensor).
As a result, there is a long felt need for an improved satellite controller that overcomes the previously described limitations, as well as other limitations not specifically mentioned.